¿ªÔÆÌåÓýThanks all for the replies.? Well, this afternoon I went through the IF alignment procedure again.? The null was reconfirmed as at 456.380.? Moving on to step 3, I switched the selectivity to sharp, but this time adjusted the signal generator frequency for the maximum output, rather than left the generator at 456.380.? The peak was at 455.380.? I then re-peaked all the other adjustments at that frequency (leaving the first one alone).? The SX-110 appears to be working fine, and the crystal filter seems to be operating as it should (or close enough).? The main source of confusion in Hallicrafters¡¯ alignment instructions is the ¡°NOTE¡± just below step 2 ¨C adjustment ¡°A¡± is not really adjusted to ¡°the frequency of the crystal¡±.? It¡¯s aligned to the frequency of the notch that may be located above or below the actual crystal frequency.? From step 3 onward, the adjustments are for the actual, exact crystal frequency.? At least, that¡¯s how I read it at this point. ? 73 ¨C Steve, KW4H ? From: <[email protected]> on behalf of don Root <drootofallevil@...> ? Richard, Steve etc too; ??the attachment that Steve sent is a .png .. pretty common now ; don¡¯t see any djvu and it opens well here and is readable. The attachment is the specific alignment procedure for the sx-110 I presume. IF you read it, you can address the question more specifically I save it as a .jpg and attached try that. 73,,? Don VA3DRL ? From: [email protected] [mailto:[email protected]] On Behalf Of Richard Knoppow
Sent: Thursday, November 10, 2022 3:51 PM To: [email protected] Subject: Re: [HallicraftersRadios] SX-110 Alignment Puzzle ? I can't open deja vu on my cell phone. Most receivers with single crystal filters adjust the IF to the crystal frequency.? ?A very few,? like the Collins 51J series need to have an exact IF frequency due to the way the tuning is done but this is very rare.?? Despite the discussion about signal generator calibration and stability it should be possible to align a simple IF with a service grade generator.? The crystal establishes the frequency. Since the overall bandwidth of the IF is considerably wider than the crystal great precision is not necessary.?? In most cases the crystal stage will have input tuning, a loading adjustment to set broadest crystal bandwidth, and maybe a neutralizing adjustment to center the phasing notch.?? Some earlier receivers have essentially a fixed crystal bandwidth and fixed phasing adjustment.? These use the original Lamb circuit.? The adjustment procedure is rather different from the later Hammarlund type filter.? Can be confusing but I don't think the earlier filter was used after aboutb1950. ? ? ? ? ? |
